Description

Would it be possible to add delivery status notification support, so that we could enable delivery proof.

https://www.rfc-editor.org/rfc/rfc1891

It requires the server to support the DSN extension and if option is enabled for the mail, change the RCPT TO command to:

RCPT TO: email@example.com NOTIFY=SUCCESS,FAILURE,DELAY

Which could notify expeditor in case of success, failure or delay.

Example

$email->to('email@example.com', [DSN::SUCCESS, DSN::FAILURE, DSN::DELAY]) // same for addTo